Author Archives: Brad

About Brad

A computer scientist deeply involved in Unix/Linux systems, networking, and electronics.

PCI, Magento, and Storing Credit Card Information

The question of whether you can store credit card information within Magento comes up a lot here at Nexcess. The answer to this question is unfortunately not very clear when looking for an answer elsewhere including on the Magento website. … Continue reading

Posted in Magento, Security | Leave a comment

Choosing a Load Balancing Solution

When a website reaches the point where a single web server can no longer handle the amount of traffic to the content or services it provides you must find a way to reliably distribute its load over two or more … Continue reading

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Testing Network Performance and Throughput with Iperf

Scenario 1: You you have two servers located a large geographical distance apart, say one in The US, the other in the UK. You are copying a large file between these two locations via scp but you are only averaging … Continue reading

Posted in Linux | 1 Comment

Monitoring Linux Bandwidth Utilization with IPTraf and Iftop

I often find myself needing a simple tool to diagnose TCP and UDP connection issues in real time. While tcpdump is an excellent tool for debugging issues at the packet level, a higher level tool is often better to diagnose … Continue reading

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Configuring MySQL Replication

The native replication built into MySQL is a powerful tool to keep an identical copy or copies of a database across multiple servers. MySQL replication is useful if you want have an exact copy of a live database for backup … Continue reading

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Using IPMI Tools to Monitor System Hardware

IPMI is the Intelligent Platform Management Interface which is an open standard that is integrated into most systems by hardware manufacturers. IPMI can provide real time hardware information including system temperatures, voltages, fan speeds and hardware status, along with identification … Continue reading

Posted in Hardware | Tagged , , , , , , , | 3 Comments

Optimizing APC Cache Settings for Magento

APC (Alternative PHP Cache) is an opcode cache for PHP that works very well to speed up page loads when used on servers running Magento. There are many opcode caches available (APC, accelerator, xcache, etc) which can be used with … Continue reading

Posted in Magento, php | Tagged , , , , , , , , | 5 Comments

Configuring and Using Dell DRAC Cards in Linux

The Dell DRAC (Dell Remote Access Card) is a powerful piece of hardware for remote server management. Utilizing a DRAC card, you can have total server control from remote locations including control to power on or off the server as … Continue reading

Posted in Apache, Hardware, Linux | Tagged , , , , | 1 Comment

Configuring Memcached in Magento 1.4

In the Magento 1.4 release, the memcached backend configuration has changed. There are now more options listed than in previous Magento versions. Some confusion has resulted in how to configure memcached in this new version as the previous configuration for … Continue reading

Posted in Magento, php | Tagged , , , | 2 Comments

Changing Your Linux I/O Scheduler

When performance tuning any modern Linux system, selecting a proper I/O scheduler is an important but often under looked optimization. Linux comes configured with the cfq (Completely Fair Queuing) scheduler which has been optimized for best performance over a wide … Continue reading

Posted in Linux | Tagged , , , , , , | 2 Comments